More dead code removal (using -Wunreachable-code)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148578 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/MCDisassembler/Disassembler.cpp b/lib/MC/MCDisassembler/Disassembler.cpp
index f156760..9eb99d2 100644
--- a/lib/MC/MCDisassembler/Disassembler.cpp
+++ b/lib/MC/MCDisassembler/Disassembler.cpp
@@ -18,6 +18,7 @@
 #include "llvm/MC/MCRegisterInfo.h"
 #include "llvm/Support/MemoryObject.h"
 #include "llvm/Support/TargetRegistry.h"
+#include "llvm/Support/ErrorHandling.h"
 
 namespace llvm {
 class Target;
@@ -163,5 +164,5 @@
     return Size;
   }
   }
-  return 0;
+  llvm_unreachable("Invalid DecodeStatus!");
 }